docs: def get_imports(self, option):
          """
          See if we have been passed a set of currencies or a setting variable
          or look for settings CURRENCIES or SHOP_CURRENCIES.
          """
          if option:
              if len(option) == 1 and option[0].isupper() and len(option[0]) > 3:
                  return getattr(settings, option[0])
              else:
                  codes = [e for e in option if e.isupper() and len(e) == 3]
                  if len(codes) != len(option):
                      raise ImproperlyConfigured("Invalid currency codes found: %s" % codes)
                  return codes
          for attr in ('CURRENCIES', 'SHOP_CURRENCIES'):
              try:
                  return getattr(settings, attr)
              except AttributeError:
                  continue
          return option